Chip cards or integrated circuit cards, both of which are commonly known as smart-cards, TPM (trusted platform Module) ICs, or the like, are devices with an embedded integrated circuit, such as a processor and/or limited capacity, non-volatile memory device. The memory device may be an EEPROM (electrically erasable programmable read only memory) or the like, and it may store an operating system for the processor as well as smart-card applications, such as electronic banking applications, telephone applications in the case of SIM (subscriber identity module) smart-cards, or the like. The memory device may also store user authentication protocols, personalization data, such as telephone or bank account data or the like, user data, such as financial data or the like, private data, such as private keys and/or certificates used in various encryption techniques, etc. User data may be secured using a PIN (personal identification number) or a password as an access control measure. In order to access the protected data stored in the card's memory device, a user must be authenticated by providing the correct PIN or password.
Although smart-card integrated devices often contain memory devices, as mentioned above the capacity of such memory devices is often very limited. Therefore, smart-card devices with larger and more costly embedded integrated memory may be needed in order to meet a demand for increased storage capacity for storing additional and/or more complex applications, user data, etc.
FIG. 1 is a block diagram illustration of a prior art integrated circuit, such as an integrated smart-card device 100, a SIM card, an electronic transaction card, an electronic identification card, a trusted platform Module (“TPM”), or the like, of the prior art. A central processing unit (“CPU”) 105 is embedded in smart-card device 100 and may include a processor 110 and an integrated random access memory (“RAM”) 120, a non-volatile memory 115, such as an EEPROM or flash memory, and a read only memory (“ROM”) 125. The processor 110 may include a cryptography engine 126, such as an advanced encryption system (“AES”) encryption engine, as a portion of access control circuitry of CPU 105, that can perform AES protocols, user authentication protocols, such as Public Key Infrastructure (“PKI”) authentication, encryption and decryption of data, etc. An input/output interface 127 is in communication with the CPU 105 and may be a USB (universal serial bus) interface for connecting directly to a host, such as a personal computer, a contactless interface, an ISO 7816 interface for use with an ISO 7816 card reader, etc. The ROM 125 typically stores the operating system of smart-card device 100. The smart-card device 100 may also include a file management system 130 that may be used to manage the address space of the non-volatile memory 115, and a key management system 135 for managing and storing one or more encryption and/or decryption keys, such as one or more AES encryption and/or decryption keys or the like. The non-volatile memory 115 or the key management system 135 may store private keys, certificates that may include public keys as part of public/private key encryption, applications, such as electronic banking applications, telephone applications, etc. The non-volatile memory 115 may further include upgrades or patches for the smart-card operating system.
During operation, the smart-card device 100 is placed in communication with a host via a card reader, for example. An identifier, such as PIN or password, is input into the host by as user. The reader may then pass the user-entered identifier on to the smart-card device 100 for verification so that the smart-card can authenticate the user. The smart-card device 100 then indicates to the host that the user is either authenticated or not authenticated. Alternatively, the smart-card device 100 may be in direct communication with the host via a USB interface, for example. In which case, the identifier is input into the host and is then passed directly to the smart-card device 100 via the USB interface for authentication of the user. After user authentication, the processor 110 either decrypts data from the non-volatile memory 115 for output to the host, or it encrypts data received from the host for storage in the non-volatile memory 115, e.g., using one or more encryption and/or decryption keys, such as AES keys, from the key management system 135.
Although the smart-card device 100 includes the non-volatile memory 115, the capacity of the memory 115 is normally very limited. Therefore, larger and more costly embedded integrated memory may be needed in order to meet a demand for increased storage capacity for storing additional and/or more complex applications, user data, etc. This could be provided by including a separate non-volatile memory device packaged with, and coupled to, the smart-card device 100. However, although it may be relatively easy to protect data stored in the memory 115 of the smart-card device 100, it is substantially more difficult to protect data by encryption or other means if the data are stored in a separate memory device that is packaged with the smart-card. In part, the difficulty of protecting data stored in a separate memory device is due to the fact protection algorithms and the cryptography keys that are normally used by such algorithms reside in the smart-card device 100. It may be possible to obtain access to interconnections between the smart-card device 100 and the memory device, which would allow the interconnections to be probed to obtain the signals coupled between the smart-card device 100 and memory device. A knowledge of these signal can allow a third party to obtain access to the otherwise protected data. Additionally, it may be difficult to protect an external memory against intrusion to the same extend that smart-card devices can and commonly are protected against intrusion and tampering. For example, smart card-devices typically include integrated sensors that protect against physical attacks, such as tampering with the device trying to extract information from it will cause the device to malfunction.
There is therefore a need for a system and method for protecting data stored in an integrated memory device that is packaged with a smart-card device to provide a smart-card having a large capacity of protected data storage.